1. Field of the Invention
The present invention relates to portable computing devices and, more particularly, to charging batteries of portable computing devices.
2. Description of the Related Art
A computing device often includes one or more batteries to supply power to the computing device. Those computing device that can use batteries to supply power to operate the computing device are referred to as portable computing devices. Portable computing devices pertain to a wide range of devices, including portable computers (various sizes), wireless phones, etc.
Normally, these portable computing devices use rechargeable batteries as the primary source of power to the device. The portable computing device typically are also able to couple to an alternating current (AC power source with an AC adapter. The AC adapter plugs into a electric wall socket and converts incoming AC power into DC power which is used to power the portable computing device and/or charge the rechargeable batteries within the portable computing device.
Conventionally, these batteries take a considerable amount of time to fully charge. One reason why the conventional charging is so slow is that the amount of power varies over the charging cycle as the battery voltage changes but the charging current remain fixed at a safe level. With this approach, the fixed current level is set to a rather low level so that when the portable computing device is active it will not be starved for power by the charging of the battery. If the portable computing device were to be starved for power during its operation, then the portable computing device would fail, crash or otherwise cease to operate.
Thus, there is a need for charging techniques that are able to better utilize available power to charge batteries.